1. Field of the Invention
The present invention relates to a hollow golf club head having both a variable center-of-gravity position and a variable weight.
2. Description of the Related Art
Japanese Patent Laid-Open No. 9-28844 proposes a conventional hollow golf club head having a variable center-of-gravity position. The hollow golf club head disclosed in Japanese Patent Laid-Open No. 9-28844 is configured such that a weight member which is threadably fitted on a threaded rod can be moved and adjusted in one of the forward, backward, left, right, upward, and downward directions of a hollow metal head body by inserting the weight member into the hollow portion of the metal head body, and rotating the threaded rod.
The golf club head disclosed in Japanese Patent Laid-Open No. 9-28844 mentioned above includes a mechanism which adjusts the weight of the hollow metal head body to be formed by rotating the threaded rod to move the weight member into the hollow portion of the metal head body. With this mechanism, in adjusting the center-of-gravity position of the metal head body after forming the metal head body, the characteristics of the golf club can be continuously changed with little change in total weight and swing weight balance of the golf club by rotating the threaded rod to move and adjust the weight member in the forward, backward, left, right, upward, and downward directions of the metal head body.
Unfortunately, the golf club head disclosed in Japanese Patent Laid-Open No. 9-28844 has an invariable weight although it has a variable center-of-gravity position.
To change the center-of-gravity position of a golf club head using a weight member, the center of gravity of the golf club head can be set at the same position using either a method of concentrated loading by disposing a weight member at one position, or a method of distributed loading by disposing weight members at a plurality of positions. However, the golf club head disclosed in Japanese Patent Laid-Open No. 9-28844 can employ only the former concentrated loading method.